Study on cross-reactivity to the para group

Monro Picardo, Carlo Cannistraci, Antonio Cristaudo, Clnara De Luca, Baldassarre Santucci

Research output: Contribution to journalArticle


In 80 patients, positive to at least one hapten of the para group (para-phenylenediamine, diaminodiphcn-ylmethane, benzocaine, PPD mix), patch tests were carried out with freshly prepared solutions of para-phenylenediamine (PPD) and of 3 selected aromatic compounds related structurally to PPD (para-aminophenol. ortho-aminophc-nol, hydroquinone). The number of positive reactions correlated with the rate of decomposition of the substances as evaluated by high-pressure liquid chromatography. PPD. which was almost decomposed after 24 h. gave the highest number of positive reactions, followed by ortho-aminophcnol and by para-aminophenol. while hydroquinone. which was oxidized to the extent of 35%. did not give any reactions. To evaluate if a different rate of oxidation can modify the patch test response, in the same patients and in 10 normal volunteers, tests were carried out with PPD solutions containing the oxidizing agent silver oxide (0.1%). By this procedure a significant increase in the number of positive responses was observed. The results suggest that the rate of decomposition and therefore the amount of quinone(s) generated, might be the key to eliciting patch test responses to oxidizablc aromatic haptens.

Original languageEnglish
Pages (from-to)104-108
Number of pages5
Issue number2
Publication statusPublished - 1990


  • Hydroquinonc
  • Ortho-aminophcnol
  • Ouinones
  • Oxidation products
  • Para group
  • Para-aminophenol
  • Para-phenylcncdiaminc

ASJC Scopus subject areas

  • Dermatology

Fingerprint Dive into the research topics of 'Study on cross-reactivity to the para group'. Together they form a unique fingerprint.

  • Cite this

    Picardo, M., Cannistraci, C., Cristaudo, A., De Luca, C., & Santucci, B. (1990). Study on cross-reactivity to the para group. Dermatology, 181(2), 104-108.